Some feed businesses have never been inspected, while others have not been inspected in more than 5 years, according to the GAO report, issued in March. In addition, the FDA does not usually test cattle feed for banned material, and the agency has not always alerted other federal agencies and the states when it learned that cattle might have been given feed containing such material.

"We believe that the problems described in this report are serious and that, given the fact that BSE has been discovered in North American cattle, breaches in FDA's oversight of the feed-ban rule place US cattle at risk for BSE," the report states. But the FDA said the problems are not significant enough to pose a serious risk.

BSE, or mad cow disease, spreads when cattle eat feed containing the remains of infected animals. To prevent this, in 1997 the FDA banned the use of most proteins from mammals in feed for cattle and other ruminant animals. (However, cattle blood, milk, restaurant plate waste, and gelatin can still be used in cattle feed.)

The sole US case of BSE so far was discovered in December 2003 in a Canadian born cow in Washington state. The discovery promoted the US Department of Agriculture (USDA) to add some new rules to keep infective material out of the food supply and to greatly increase testing of cattle for the disease. The USDA and FDA banned the use of specified-risk materials—high-risk cattle parts such as the brain, spinal cord, and tonsils—in human food, but they can still be used in feed for nonruminant animals and pets.

Under the FDA feed ban, firms must clearly label feed and feed ingredients that may contain banned proteins with the statement "Do not feed to cattle or other ruminants." Firms also must have methods for preventing mixing if they handle feed for both nonruminant animals (whose feed is still allowed to contain cattle protein) and ruminants.

Sens. Tom Harkin, D-Iowa, and Dick Durbin, D-Ill., requested the GAO report. To gather information, the agency reviewed 404 FDA inspection reports, interviewed FDA officials, and watched FDA and state inspectors conduct 19 feed-facility inspections in 12 states, the report says. The GAO also surveyed state agency officials in 38 states that inspected feed facilities under contracts with the FDA last year.

The report says the FDA has remedied some problems that the GAO had described in a report in early 2002. The agency now has uniform methods for inspecting feed facilities and training both FDA and state inspectors, plus better methods for tracking inspection results.

However, the GAO finds that the enforcement program still has serious weaknesses:

* About 14,800 feed manufacturers and other feed-industry businesses have been inspected so far, but the FDA knows there are others that have not been inspected, and it has no "uniform approach" for finding them. * The FDA has not reinspected about 2,800 feed businesses in the past 5 years. Many of those were farms that are considered low-risk, but about 400 were feed mills, where the risk of violations is deemed higher. * The FDA's inspection guidelines do not call for routine testing of cattle feed for banned material. FDA officials said the presence of exempt items such as cattle blood in feed makes such testing useless, but officials in some states said such testing would be useful at firms that say they don't use exempt items. * The FDA has not always alerted the USDA and states when it learned that cattle might have been given feed containing banned material, even though the FDA's guidelines call for such notifications. In one case, an inspector found that a firm had been using banned material for nearly a year; the firm issued a recall, but the FDA did not notify the USDA or the state.* The FDA has given incomplete information about feed-ban compliance to Congress and the public. For example, in January 2004 the agency reported a 99% compliance rate but failed to note that the rate was based on inspections of only about 570 firms. And in some cases, FDA has counted firms as being in compliance even when the firms have placed no warning labels on feeds that contain prohibited material.

The report says that in commenting on a draft version, the FDA said it believed "that the weaknesses we identified are not sufficiently material to place U.S. cattle at risk for BSE and that its risk-based inspection approach assures adequate oversight of the feed-ban rule."

The report includes nine recommendations to correct the various problems. The FDA disagreed with four of the recommendations, including the advice that the FDA should test feed samples when it inspects feed businesses. Tests cannot detect the prions that cause BSE, but they can detect animal material, which would help in verifying inspection results, the GAO contends.